Last lathe



.Dec. 19, 1922..

' 1,438,978. F. s. BUCK.

LAST LATHE.

FILED JUNE 14. 1919.

2 SHEETS-SHEET I Dec. 19, 1922.

- F. s. BUCK.

LAST LATHE.- FILED JUNEM. r919.

2 SHEETS-SHEET 2.

atented rnann s. noon or srnrnerrniin, vnniiron'r, assienen r0 rrrz-niurran DOUBLE river Las'r COMPANY, or Minoan,

MAINE, a conronarron or arian nns'r Learns.

Application filed June at,

To all whomitmay concern: a a Be it known that I, FRANK S. Been, a citizen of the United States, residing at Epringfield, in the county of Windsor and State of Vermont, have invented certain Improvements in Last Lathes, of which the following description, in connection with the accompanying drawings, is a specification, like reference charactersonthe (drawings indicating like parts in the several figures. i a

This invention relates to machines for the production of irregular objects from a pattern, and is herein disclosed as embodied in a last lathe. y i

Great difficulty and expense have been caused in the manufacture oflasts prior to the present invention by the failure of the commercially obtainable machines to repro duce accurately those parts of, the mod having sharp concavities, such, for ex ample, as portions of the heels andinsteps in womens lasts. The reason was that the 10-inch model wheel found on these machines would bridge over a sharply concave hollow and reproduce iton aiS-inch radius. The improperly reproduced portions had then to be hollowed out and finished by hand, which entailed inaccuracy and increased expense.

tlhe simple reduction in sire of. the ju odel Wheel and cutter was not possible because, among other rcasous, the axes of the work and cutter. were thereby hroiughtso' close together that the work, for exz iuiple at the top of the cone, would interfere with the cutter axis and its co-operi ing elements when the cutter was treating the lower parts of the last.

The present invention contemplates the production of a machine having a model wheel of arbitrarily sharp curvature to enable the wheel to reach the bottom of the sharpest concavity to be found on a last at the same time having a cutting instrumentality which will follow the model wheel without any of the difficulties which had been encountered in previous efforts to solve the problem. i

I accomplish this resultby the CODSllrllQ tion of a cutting instrui'nentality which has 1919. Serial no. 804,269.

no portions in-the vicinityofthe work extending in the direction of the axis of the work farther than does the model. wheel itself. The cutter is therefore capable of maintaining .thesame relation to the work that the model wheel does to the model. without danger of interference; I prefer ably arrange the cutter for moyement about a physical axis .not materially longer than that of the model wheel. i

In the illustrated embodiment of the invention the. cutter is mounted on an endless belt passing over a wheel or guide near the work, and driven from an instrumentality remote from the work. Thus I am enabled to use a cutter of conveniently smalleilecthe diameter .without interference between its. driving means and the work.

These and other features of the invention comprising various arrangements and C0111".

binations of parts will be understood from the following description of a preferred embodiment thereof, selected fonpurposes ofillustration, andshown in the drawings in which, I v. M v Figelis a side elevation of the machine;

Fig. Q-isadetail of the cuttinginstrumentality; i

8 is a cross-section on the line 3 of Fig. 2; w vl lig. 4i is a detail of a cutter;

:lfilig. 5 is aplau showing the relation of theiuodel wheelaiul cutter iustrumentality.

llhe mainframe l0, swing "fl'im'ie l model carriage Ll, cutter carriage "llhdrivingniechanisin iucludingthe drum l8, width grading mechanism 20, and length grading mechanism 22, are all of ordinaryGilman last lathe construction. The model wheel 2% is mounted in the usual manner upon the model wheel carriage. The cuttercarriage has pedestals 26 extending upwardlyand carrying at its top bearings 28 for a shaft 30 upon whichyare mounted a pulley 32 and a sprocket wheel 34 having teeth '36.

The pedestals 26 carry a forwardly ex tending arm 38 adjustably mounted upon them by means of the screwsdO. This arm carries at its forward end short shaft l), 1.00

upon which mountedguide wheel l t, and carries also guides to and d8 whichare ar-j ranged tangentially. between the wheels 44 and 34;. A sprocket chain is arranged to run upon these wheels and guides. The sprocket chain is composed of units each comprising two side plates 52 embracing a link 54:, as is customary in sprocket chams.

Each link 54 has anupstanding lug 56 upon which is bolted a cutter 58 shown as a half-cup" having a substantially semicircular cutting edge 60. p

. The curvature of the cutter 58 is substantially that of a cross-section of the;

model wheel made by a plane passing through the axis thereof and the cutter is so i shaped that at the time that it is rolling over the wheel 44 its cutting edge 60 is farther from the axis of the shaft 42 than its heel 62 in order'to provide proper clear ance. v

A belt 6% passes over the pulley 32 and the drum 18' and drivesthe shaft 80 in the usual manner as the cutter carriage isdriven along the frame. The wheel 44l- 151; so

proportioned that the cutting edge 60, as

its cutter 58 passes around the wheel, will describe a surface of revolution substantially identical with the periphery of the modelt wheel. These parts -may be made physically as small as is necessary in cutting lasts without sacrificing strength, rigidity and safety in operation. It has been found byexperience that a model wheel of three or three and one-half inches in diameter is sufliciently small to reachthe bottom portions of any concavitiesthat occur in commercial last cutting and I'have found it quite" practicable to constructithe apparatus described upon such a curvature.

The wheel dl'and guide 38 together occupy no more thickness than that of the t model Wheel itself and its attendant parts so that the cutter can be continuously main;

tained in the same relation tothe work as;

the model wheel to the model; 'lhe cutter will therefor-ego anywhere upon the work i I that the IlllOLlBl wheel will upon the model.

and it is iiu iiossibh-i for ahigli utrt of the last to hang up upon some portion of the cutting instrumentality when the cutter itself isoperating upon a low portion such as the top of the toe. The great number of cutting .a model followinginstrumentality having a diameter approximately that of a model last,

and a cutter instrumentality rotating on, an

axis substantially parallel to/that ofithe work and having the same effective diame ter, neither the cutter instrumentality nor its supporting mechanism having any parts in 2. In a machine of the class describedf model and work holding instrumentalities, a model following lnstrumentahty, having a diameter approximately that of a model last and a cutter instrumentality having the same effective diameter operating upon a. spindle parallel to that of the work, said spindle not being substantially longer than the thickness of the effective portion of the model following instrumentality. I Y 3. In machine of the classfdescribed model and work holding instrumentalities, a model following instrumentality, having a diameter approximatelythat of a model last, and a rotating cutter'instrumentality having the'sameelfective diameter, the spindle of thecuttin g instrumentality beingof not substantially greater length than the thickness of the effective portion of the model following instrumentality. i

4 In a 'machine of the class described, model. and work holding instrrnnentalities, a model following i1strumentality having a. diameter approximately that of a model last, and a flexible cutter instrumentality having metallic cutting edges and having the same effective diameter, and adriving means for the cutter instrumentality lying substantially in the plane of -movement of the cutter instrumentality. v

5. In a machine of the class described model and work holding instrumentalities, a modelfollowing instriunentality, a flexible cutting instrumentality comprising metallic cutting. edges, and a guide vconstructed and arranged to hold the cutting instru'mentality with regard to the work in similar relation.

to that between the. model and the model followinginstrumentality. I

(3. In a machine of the class 'describmh model and work holding instrumenta-lities, a model following wheel having approximately the diameter of a model last,an endlessbelt carrying a. work treating means and a guide for holding the means in a path of curvature substantially equal to that of the periphery of the model following instrumentality. i g i I 7. In a machine of the class described, model and work holding instrumentalities, a model wheel, an endless flexible cutter carrier arranged to follow an oblong path, one end of the oblong being shaped tocorrespond to the effective surface of the model wheel and a driving means for the-carrier model wheel a guide wheel on an axis normally collinear with the model Wheel axis, a model and Work holding instrumentalities, a, drive Wheel and an endless cutter carrying model following guide, and a chain carrying 10 belt running on the guide wheel and drive cutters on its links arranged to run in a Wheel, the guide Wheel and belt being erwith corresponding to the surface of the ranged to carry the cutters in a path corremodel following guide.

sponding to the effective surface of the In testimony whereof I have signed my model Wheel. name to this specification.

9. In a machine of the class described, FRANK S. BUCK. 

